Method of and device for cementing wells



Aug. 26, 1930. A. BoYNToN METHOD OF AND' DEVICE FOR CEMENTING WELLS ssheets-sheet 1 Filed ot. 1, 1925 INVENTOR AToRNEYs v @5o/vrom Allg. 26,1930. A, BQYNTON 1,773,941

METHOD OF AND DEVICE FOR CEMENTING WELLS Filed Oct. l, 1925 3Sheets-Sheet 2 @QQ Y www x ATTORNEYS y l (i f Aug. 26, 1930. A. BOYNTONMETHOD oF- AND DEVICE FDR CEMENTING wELLs Filed Oct. l, 1925y 5Sheets-Sheet INVENTOR /7Boy/v7'o/v,

WITNESSES 30 pump will, of course,

Patented Au'g. 26, 1930 PATENT oFF'lcE ALE-XANDER BOYNTON, OF SANANTONIO, TEXAS METHOD F AND DEVICE FOR CEMENTING WELLS Application ledOctober 1, 1925. Serial No. 59,888.

This invention relates to an improved device for cementing oil, gas andwater wells.

One of the principal objects of the invention is to provide a device ofthis character L'. which may be conveniently used to properly cement thewell and which does not require the 'use of wooden plugs and barriers,or the raising and lowering of the well casing.

Heretofore in the art it has been proposed :e to carry out thecementation of wells by the use of a process wherein the cement wasspaced from the mud fluid by means of two wooden plugs. In this oldprocess, the well casing is first let down upon the bottom of the well1n order to find the bottom, and then picked up a few inches in order'that the pump may set up circulation. Just at this point in the processdifliculty is not infrequently encountered since it is not alwayspossible to pick up the casing. After the casing has been picked up abottom plug is inserted. Then the cement is pumped into the casing andon top of the cement a top plug is placed. The mud fluid is thenpumpedin on top of the top plug until the bottom plug strikes the bottomof the well. The casing having been picked up, say six inches from thebottom as above described, and thebotton. plug being say twelve incheslong, the stall when the bottom plug strikes the bottom of the well.Then the casing is picked up again to a point say six inches above theto ofthe bottom plug and the pump is starte again and 'run until 85 thetop plug strikes the bottom plug.

The casing is aptto stick or freeze at any time. If the casing could notbe pulled up the second time, the cement is trapped and must be removed.The pump again stalls 40 when the top plug strikes the bottom plug,

because the bottom plug is about twelve inches long, and as just stated,the casing has been picked up to a point six inches above the top of thebottom plug. When the top v and bottom plugs come together as stated,the

cement is all outside of the casing. Then the casing is lowered to thebottom. Sometimes, however, it can not be lowered. If no trouble isencountered in picking up the casing twice as set out and then lettingit 'down again, this process' works all right unless one or both of theplugs should stick in the casing. Serious difliculty has beenencountered due to the plugs sticking. The plugs `are made of wood, andthekind of wood of which the plugs are constituted varies. Differentkinds of wood expand to different degrees, but all plugs expand more orless when exposed to the mud fluid, and the amount of ex;I pansiondepends not only upon the character of the wood, but also upon themoisture contained in the wood at the time the plugs are used. Moreoversticking of the plugs results not only from swelling and expansion, butmay also be caused by any imperfection in the casing, Such as dents,slivers or bends.l

Frequently casings become distorted from great outside pressure, and itis not uncommon in deep wells to have the casing collapse when greatpressure of water or mud fluid on the outside comes against the cas- 4ing and bends it or partially collapses it. Not only must the quality ofwood and its moisture content be always observed with care, but thelgreatest care must always be'used to accurately caliper the/plugs theproper diameter in order to avoid sticking of the plugs,

if too large, and leaking of cement past the plugs if too loose. Forthese reasons it has been found that the process heretofore proposed inthe art is very often unsatisfactory.

The present invention avoids the dificulties and disadvantages of theold process lsince o plugs are used. At the same time the pres-` entinvention insures the proper application of the cement to the properplace .oplaces and the operator isaccurately advised when thecement'ation has been completed.

Other objects and advantages reside in certain novel features oftheconstruction', ar rangement and lcombination of parts which will behereinafter more fully described and Aparticularly pointed outin theappended Figure 2 is a view similar to Figure 1 but phase of the actionof tion.

Figure 5 is a fragmentary view showing another embodiment of theinvention.

Figure 5 is a view similar to Figure 5 and .illustrating the lower partof the apparatus shown in Figure 5.

' Referring to the drawings and more particularly to Figures 1 and 2,the numeral 1 designates the well casing. At its lower end the casing isprovided with the ordinary casing shoe 2. Just above the casing shoe laperforated disc 3 is clamped in between the sections of the casing,'thep'erforations of the disc affording discharge openings 4. Centrally thedisc 3 has a boss', and the boss and disc are provided with an axialguide opening 6 in which a valve stem 7 is fitted. The valve stem 7 hasa head atv one end engaging the boss 5 and at its other end hasa head 9providing anabutment for one end of a coil spring 10, the other end ofthe coil spring engaging a washer 11 on the underside of a Valve l2. Thespring is tensioned to hold the valve 12 up against the under side ofthe plate 3 so that the valve closes the discharge opening 4 of theplate. The plate 3 may be made of soft brass or other suitable metal sothat it may be drilled out after cementing has been completed. Thisassembly is commonly known as a back pressure valve.

A valve seat of wood, brass, or other suitable material is provided andhas an outwardly directed annular flange 21 engaged andheld between theadjacent ends of the sections 16 and 17. The body of the valve seat 20is preferably a driving fit in 'the cas- I .ing and for the purpose offurther securing the valve seat in position transversely eX- tendingopenings may also be formedy in the valve seat and in the section 17 andthese openings filled with babbitt 22. The valve seat 20 has a beveledvalve facin 23 intermediate its ends, and the upper en is formed with abeveled guide surface 24. A differential float providing a combinedsignal and valve is designated at and is coo erable with the valve seat20. Asshown in igures 1 and 2, 'this combined valve and signal-25 may bea ball or body of hard rubber, hard in view of the great difference inthe specific gravity of the mud' fluid and of the cement,-

cement as usually mixed and used ranging from 1.67 vto 1.85 while theordinary mud fluid ranges vfrom 1.10 to 1.20.

The embodiment of the invention shown in Figures 3 and 4 isidentical'with that illustrated in Figures 1 and 2 except that adifferent means is provided for preventing back ilow of the cement and asomewhat different 4form. of signal and valve is employed, and that inaddition to the 'elements shown in the embodiments illustrated inFigures 1 and 2, an imperforate barrier comprising a plate or disc D isfixed to the casing and obstructs the opening therethrough at a point ashort distance above the shoe. The valve 12 and its associated structureare omitted in the forni ofthe invention shown in Figures 3 and 4 and inlieu of these parts a nipple 26 is incorporated in the string of casingand is provided with a number of diametrically opposite openings 27.Only two sets of openings 27 are provided and at one set isdiametrically opposite the other. A sleeve valve 28 of rubber or otherelastic material is fitted on the nipple 26 and has an imperforateportion 'covering the opening 27. The sleeve valve 28 is held inposition by a relatively small upper retaining cup 29 and a relativelylarge lower retaining cup 30,l both cups being screw threaded on the niple. As stated the sleeve valve 28 has imper crate portions covering theopenings 27' but at points angularly spaced ninety degrees from theopen- 4ings 27, the sleeve valve 28 is formed with discharge ports 31.The valve sleeve is preferably constituted of heavy rubber or otherelastic material and is tensioned to snugly fit and firmly clamp thenipple 26. This valve, due to its elasticity, may be expanded whensubjected to pressure within the nipple to permit fluid within thenipple to pass through vthe openings 27 in the space between the outsideof the nipple 26 and the expanded or stretched valve 28 andoutthroughthe discharge port 31, but when subjected to outside pressure orto a pressure greater on the outside than on the in, the elasticity ofthe nipple will be aided by the greater outside pressure in forcing theimperforate portions of the nipple over the openings 27 thereby sealingthe openings 27. In thisl way the valve 28 serves as a check valvel andeffectively lprevents the' cement from running.

back into the casing as will be hereinafter more fully explained.

In Figures 3, 4, 5 and 5 a somewhat different form of combined valve andsignal is employed and which comprises a ball B made up of any hardnon-compressible metal or a alloy or other substance snch'as guttaperchaor an alloy of aluminum and any. other light soft metal. A handle H isrigidly and securely connected to the ball or body B and is` cut offsli-ghtly above heavier than the cement.. Cement is usua may be readilyvaried constituted of white pine or any other soft wood or similarsubstance. The handle H is shellacked or painted to prevent it fromabsorbing water and thereby changing its specific gravity while underthe great fluid pressures existing in the lower regions of the well.This type of combined signal and valve to cause it to have the exactspecific gravity required under the prevailing conditions. The problemis always to use a combined signal and valve of such specific gravitythat it will float in the cement and yet sink in the mud fluid used toforce the cement down intoplace. In modifying the combined valve andsignal 4shown in Figure 2 to cause it to have vthese properties it isplaced in the cement which has been mixed in the cement mixing boxon'the derrick floor. 'Ihe point at which the handle H becomes submergedis marked. The handle H is then this mark thus varying the materialcontent. It is to be understood that the ball B is always of a specificgravily y mixed and used at a specific gravity of about 1.7. 'Thespecific gravity of therefore be about 1.7 5 so that it will barely sinkin the heavier cement. The correct specific gravity to cause the signalball to float safely in any cement mixture is then determined asdescribed by cutting off the handle just above the point at which itsinks in the cement mixture. In this way the combined valve and signalmay be readily adapted to different cements and different mixtures ofthe same with water and sand in order to compensate for the varyingspecific gravities of such cement mixtures. Likewise thecombined valveand signal is adapted forV use with the mud fluids .produced by dierentwells and different fields and which also have varying specificgravities.

with the anni nf the invention illustrated n in Figures 5 and 5 thecombined signal and valve B, the valve seat 20 and the upwardly fittingspring closed valve 12 are all einployed in the well casing insubstantially the same relation as 1 and 2 and hereinbefore described,except that these parts are positioned well up in the well casing sincethe arrangement sliownvin Figure 5 is designed specifically for use incementing the so-called one string wells, that isthe-wells lwhichare'drilled in through the oil sands before they are cemented. In thearrangement shown nipple 35 is ineorporatpd in the well casing, theupper end of the .nipple 35 engaginof the perforated disc 3." At thelower end 0I the nipple an impe-rforate' barrier in the form of a brassplate 36 1s ixedly secured in the well casing.

With this embodiment of the invention it is essential to prevent thecementfrom flowing down between ball B should` that illustrated inFigures in Figure 5 a perforatedA the outside of the casing.A

and, the wall or formation ofthe well hole after it has been placed, andfor this purpose laminated sealing members 37 are provided. The detailsof these sealing members 'form the subject matter .of a co-pendingapplication, and here it is sufficient to note that-these laminatedsealing members are designed to shear off the sha-le and otherformation. defining the wall of the'well causing impaction of thisslieared off material between the sealing members, whereby to preventthe ow'of cement down past the sealing members through the oil producingsands. The upper sealing member is slightly larger than the lower;otherwise the sealing members are identical.

In order to prevent down flow of the cement even though members shouldfail to fulfill their function, a bootleg packer 40 is provided andconsists of a tubular structure of fabric mounted on the well casingjust above -the sealing members-37, the lower end of the bootleg packerbeing fixed onthe well casing by a wrapping 41 ofrwire. The packer 40enlarges towards itsv upper end and the Lipper end thereof is open andis located opposite the intermediate perforations of the nipple 35. Thebootleg packer has its upper ready to receive the cement and check andstop the down flow of the same should conditions arise which wouldpermit the cement to flow past the sealing members 37.

the laminated sealing open end always In all embodiments of theinvention, they i the well casing, and the combined signal .-ball andvalve -25 is placed on to of the fluid cement mixture where it will goatonly partially submerged. The casinT is then connected to the pump andmud flbuid is pumped on top of the cement to force the cement downthrough the well and through the opening of the valve seat 20.

The course which the cement takes after being passed t rough the openins of the ball valve seat depends on the em odiment of the inventionwhich is employed. With the embodiment shown in Figures 1 and 2,' thecement,after passing through the openings in the valve 12 and outunderneath the casin shoe 2. The valve 12 permits down How o the cementbut prevents back flow thereof.

the ball valve seat, passes down past With the embodiment of theinvention shown openings 27 'of the nipple and out through the openings31. At this point it should be borne in min that the pump used to forcethe cement into the Well operates under a pressure of from three hundredto four hundred pounds per square inch, which insures the properoperation of the heavy rubber sleeve valve 28. Back flow of the cementinto the well casing is prevented by the operation of the sleeve valveWhen practically all of the cement has been displaced from the Wellcasing the differential float which serves as a combined Y signal andvalve will engage and snugly fit on the bevelled facing 23 of the valveseat 20 and the pump will stall, thereby indicating to the operator thatthecement job has been completed. The cement cannot flow back into thecasing and Where the cementation is carried out above the bottom of theWell, it cannot flow down between the outside of the well. casing andthe wall of the well hole.

WithA this arrangement the Casin is not picked up, but after it isproperly p aced in position it is left undisturbed, thus the propercementation of the Well does not depend on the ability of the operatorto manipulate the casing. No plugs are used and consequently nodifficulty is encountered by virtue of swelling plugs. The relativelysmall combined signal and valve is well adapted to pass any obstruction,dents or imperfections 'in the well casing.

What I claim is:

1. A device for cementing Wells including a Vdifferential float havingvariable means whereby its specific gravity may be readily changed, andcomprising a ball and a handle, said handle being adapted to be cut oito vary the specific gravity of the assembl 2. A 'device for cementingWells inclu ing a differential float having variable means whereby itsspecific gravity may be readily changed, comprising a ball of hard rigidsubstance and a wooden' handle.

ALEXANDER BOYN TON

